Buggy code:
public class ProxyStepHandler implements NewStepHandler { private final NewProxyController proxyController ; public ProxyStepHandler ( final NewProxyController proxyController ) { } @ Override public void execute ( NewOperationContext context , ModelNode operation ) { OperationMessageHandler messageHandler = new ProxyStepHandler . DelegatingMessageHandler ( context ) ; final AtomicReference < NewModelController . OperationTransaction > txRef = new AtomicReference < NewModelController . OperationTransaction > ( ) ; final AtomicReference < ModelNode > preparedResultRef = new AtomicReference < ModelNode > ( ) ; final AtomicReference < ModelNode > finalResultRef = new AtomicReference < ModelNode > ( ) ; final NewProxyController . ProxyOperationControl proxyControl = new NewProxyController . ProxyOperationControl ( ) { @ Override public void operationPrepared ( NewModelController . OperationTransaction transaction , ModelNode result ) { txRef . set ( transaction ) ; preparedResultRef . set ( result ) ; } @ Override public void operationFailed ( ModelNode response ) { finalResultRef . set ( response ) ; } @ Override public void operationCompleted ( ModelNode response ) { finalResultRef . set ( response ) ; } } ; final ModelNode execute = operation . clone ( ) ; final PathAddress addr = PathAddress . pathAddress ( execute . require ( ADDRESS ) ) ; if ( ( addr . size ( ) ) > 0 ) { final PathAddress newAddr ; if ( ( addr . size ( ) ) == ( proxyController . getProxyNodeAddress ( ) . size ( ) ) ) { newAddr = PathAddress . EMPTY_ADDRESS ; } else <START_BUG> if ( ( proxyController . getProxyNodeAddress ( ) . size ( ) ) < ( addr . size ( ) ) ) { <END_BUG> throw new IllegalArgumentException ( ( ( addr + "<seq2seq4repair_space>does<seq2seq4repair_space>not<seq2seq4repair_space>appear<seq2seq4repair_space>to<seq2seq4repair_space>capture<seq2seq4repair_space>proxy<seq2seq4repair_space>" ) + ( proxyController . getProxyNodeAddress ( ) ) ) ) ; } else { newAddr = addr . subAddress ( proxyController . getProxyNodeAddress ( ) . size ( ) ) ; } execute . get ( ADDRESS ) . set ( newAddr . toModelNode ( ) ) ; } proxyController . execute ( execute , messageHandler , proxyControl , new ProxyStepHandler . DelegatingOperationAttachments ( context ) ) ; ModelNode finalResult = finalResultRef . get ( ) ; if ( finalResult != null ) { context . getResult ( ) . set ( finalResult . get ( RESULT ) ) ; context . getFailureDescription ( ) . set ( finalResult . get ( FAILURE_DESCRIPTION ) ) ; context . completeStep ( ) ; } else { ModelNode preparedResult = preparedResultRef . get ( ) ; context . getResult ( ) . set ( preparedResult . get ( RESULT ) ) ; if ( preparedResult . hasDefined ( FAILURE_DESCRIPTION ) ) { context . getFailureDescription ( ) . set ( finalResult . get ( FAILURE_DESCRIPTION ) ) ; } NewOperationContext . ResultAction resultAction = context . completeStep ( ) ; NewModelController . OperationTransaction tx = txRef . get ( ) ; if ( tx != null ) { if ( resultAction == ( ResultAction . KEEP ) ) { tx . commit ( ) ; } else { tx . rollback ( ) ; } } } } private static class DelegatingMessageHandler implements OperationMessageHandler { private final NewOperationContext context ; DelegatingMessageHandler ( final NewOperationContext context ) { } @ Override public void handleReport ( MessageSeverity severity , String message ) { } } private static class DelegatingOperationAttachments implements OperationAttachments { private final NewOperationContext context ; private DelegatingOperationAttachments ( final NewOperationContext context ) { } @ Override public List < InputStream > getInputStreams ( ) { } } }

Fix:
if ( ( proxyController . getProxyNodeAddress ( ) . size ( ) ) > ( addr . size ( ) ) ) {